This invention relates in general to computed radiography imaging systems and relates more particularly to a computed radiography imaging system in which exposed imaging plates are scanned while moved in a vertical direction and having a simplified and integrated control mechanism for positioning and clamping a cassette and for latching and unlatching an image plate from the cassette.
Conventional film/screen radiography uses radiographic films which are not reusable. Computed radiography solves this problem by using reusable storage phosphor imaging plates, that can be exposed, read out, erased, and reused many times. Some computed radiography systems are flexible storage phosphor imaging plates which can be degraded through contact of the storage phosphor layer with plate handling rollers and the like. Another computed radiography system uses rigid storage phosphor imaging plates where plate handling mechanisms do not contact the storage phosphor layer. Although an improvement over systems using flexible imaging plates, the horizontal reading and erase path of such a system results in a computed radiography reader which is bulkier and slower than may be desirable. There is thus a need for a computed radiography system that is compact in size, has increased image plate throughput, and eliminate degradation of the storage phosphor due to the excessive handling.
There is also a need for a computed radiography reader having a simplified and integrated control mechanism for positioning and clamping a cassette and for latching and unlatching an image plate from the cassette.
According to a feature of the present invention there is provided:
A computed radiography (CR) reader comprising:
a cassette receiving station for receiving in a vertical orientation, a computed radiography cassette including a light tight cassette shell and an image plate supported by an extrusion closing off said shell, said image plate storing a latent radiographic image and being latched in said cassette shell;
a first roller assembly located on one side of said cassette receiving station;
a second roller assembly located on the other side of said cassette receiving station, cooperatively associated with said first roller assembly;
means for mounting said second roller assembly for movement towards and away from said first roller assembly;
an image plate unlatching and latching assembly; and
a cam assembly operatively linked to said means for mounting said second roller assembly and to said unlatching and latching assembly, said cam assembly being operable in a first mode when a computed radiography cassette is received in said cassette receiving station, to actuate said mounting means to move said second roller assembly towards said first roller assembly to clamp said cassette between said first and second roller assemblies and to actuate said unlatching and latching assembly to unlatch said image plate from said cassette shell;
and in a second mode to actuate said unlatching and latching assembly to latch said image plate in said cassette shell and to actuate said mounting means to move said second roller assembly away from said first roller assembly to unclamp said cassette to allow removal of said cassette from said receiving station.
The invention has the following advantages.
1. The computed radiography system is compact in size.
2. The vertically oriented computed radiography system has increased image plate throughput compared to horizontally oriented systems.
3. Degradation of storage phosphor layer is minimized.
4. A simplified and integrated cam control mechanism positions and clamps a CR cassette as well as unlatching and latching an image plate from the cassette.